Effect of temperature and strain during forging on subsequent delta phase precipitation during solution annealing in ATI 718plus® alloy

ATI 718Plus® alloy relies upon grain boundary precipitation of the delta phase in order to achieve good resistance to notch failure. Delta phase precipitation can occur when forging at subsolvus temperatures or during solution annealing. Precipitation of delta phase during solution annealing can be affected by the interaction of forging temperature and strain during hot working whereby the combination of high forging temperature and low strain can result in unsatisfactory delta phase precipitation. Additionally, delta phase precipitation can be affected by exposure to supersolvus temperatures after forging is complete. This paper describes the effect of thermal mechanical processing history on delta phase precipitation in ATI 718Plus alloy and provides guidance on best practices to achieve optimum microstructure. (AU) © 2010 by The Materials, Metals, & Materials Society. All rights reserved.